<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>二维数组转置</title>
</head>
<body>
        <script>
                var arr = [['a','b','c'],['d','e','f'],['g','h','i'],['j','k','l']];
                var res = [];
                for (var i = 0; i<arr[0].length;++i){
                    res[i] = [];
                    for(var j = 0; j <arr.length; ++j){
                        res[i][j] = arr[j][i];
                    }
                }
                console.group('转置前：');
                console.log(arr);
                console.groupEnd();
                console.group('转置后：');
                console.log(res);
                console.groupEnd();
            </script>
        
</body>
</html>